Manufacturing method of package carrier

ABSTRACT

In a manufacturing method of a package carrier, a substrate including a first metal layer, a second metal layer having a top surface and a bottom surface opposite to each other, and an insulating layer between the first and second metal layers is provided. The second metal layer has a greater thickness than the first metal layer. A first opening passing through the first metal layer and the insulating layer and exposing a portion of the top surface of the second metal layer is formed. The first metal layer is patterned to form a patterned conductive layer. Second openings are formed on the bottom surface of the second metal layer. The second metal layer is divided into thermal conductive blocks by the second openings that do not connect the first opening. A surface passivation layer is formed on the patterned conductive layer and the exposed portion of the top surface.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Divisional of and claims the priority benefit ofU.S. patent application Ser. No. 13/052,122, filed on Mar. 21, 2011, nowpending, which claims the priority benefit of Taiwan application serialno. 100101971, filed on Jan. 19, 2011. The entirety of each of theabove-mentioned patent applications is hereby incorporated by referenceherein and made a part of this specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a semiconductor structure and a manufacturingmethod thereof. More particularly, the invention relates to a packagecarrier and a manufacturing method thereof.

2. Description of Related Art

A chip package provides a chip with proper signal and heat transmissionpaths and protects the chip structure. A leadframe often serves as acarrier of a chip when a conventional wire bonding technique is applied.As contact density in a chip gradually increases, the leadframe which isunable to further improve the contact density can be replaced by apackage substrate which can achieve favorable contact density. Besides,the chip is packaged onto the package substrate by conductive media,such as metal conductive wires or bumps.

In the well-known common light emitting diode (LED) package structure,an LED chip need be packaged before the LED chip is used, and the LEDchip generates a significant amount of heat when emitting light. Giventhe heat cannot be dissipated and continues to accumulate in the LEDpackage structure, the temperature of the LED package structure isincreasingly raised. As such, the overly heated LED chip may haveluminance decay, shortened life span, or even permanent damages.Therefore, heat sinks are configured in the existing LED packagestructure, so as to dissipate heat of the LED chip.

The conventional package substrate is comprised of a plurality ofpatterned conductive layers and at least one insulating layer. Theinsulating layer is configured between two adjacent patterned conductivelayers for electrical insulation. A thermal conductive block is fixed toa lower surface of the package substrate through an adhesive layer. Inmost cases, the LED chip is electrically connected to the packagesubstrate, and heat generated by the LED chip can be conducted from thepatterned conductive layers and the insulating layer to the thermalconductive block. Since the thermal conductivity of the adhesive layerand the insulating layer is unfavorable, thermal resistance increaseswhen the heat generated by the LED chip is conducted from the insulatinglayer and the adhesive layer to the thermal conductive block, whichleads to unsatisfactory heat dissipation. Hence, how to dissipate theheat generated by the LED chip to the external surroundings in aneffective manner has become a focus to researchers and designers in thisfield.

SUMMARY OF THE INVENTION

The invention is directed to a package carrier suitable for carrying aheat-generating element.

The invention is further directed to a manufacturing method of a packagecarrier. By applying the manufacturing method, the aforesaid packagecarrier can be formed.

In an embodiment of the invention, a manufacturing method of a packagecarrier is provided. The manufacturing method includes following steps.A substrate is provided. The substrate includes a first metal layer, asecond metal layer, and an insulating layer configured between the firstand second metal layers. A thickness of the second metal layer isgreater than a thickness of the first metal layer, and the second metallayer has a top surface and a bottom surface opposite to the topsurface. A first opening passing through the first metal layer and theinsulating layer is formed. The first opening exposes a portion of thetop surface of the second metal layer. The first metal layer ispatterned to form a patterned conductive layer. A plurality of secondopenings are formed on the bottom surface of the second metal layer. Thesecond metal layer is divided into a plurality of thermal conductiveblocks by the second openings, and the second openings do notcommunicate with the first opening. A surface passivation layer isformed on the patterned conductive layer and the portion of the topsurface of the second metal layer exposed by the first opening.

According to an embodiment of the invention, the step of providing thesubstrate includes providing the insulating layer and the first andsecond metal layers that are located at two opposites sides of theinsulating layer. A thermal compression process is performed, such thatthe first metal layer, the insulating layer, and the second metal layerare integrated to form the substrate.

According to an embodiment of the invention, the step of forming thefirst opening includes stamping, routing, or laser drilling.

According to an embodiment of the invention, the thickness of the secondmetal layer is 1˜100 times the thickness of the first metal layer.

According to an embodiment of the invention, a material of the firstmetal layer is copper foil.

According to an embodiment of the invention, a material of the secondmetal layer includes copper, copper alloy, aluminum, or aluminum alloy.

According to an embodiment of the invention, a material of theinsulating layer includes resin, liquid crystal polymer (LCP), orpolyimide (PI).

According to an embodiment of the invention, the step of forming thesecond openings includes a photolithography and etching process, amechanical drilling process, or a laser drilling process.

According to an embodiment of the invention, the step of forming thesurface passivation layer includes electroplating.

In an embodiment of the invention, a package carrier suitable forcarrying a heat-generating element is provided. The package carrierincludes an insulating layer, a patterned conductive layer, a thermalconductive block, and a surface passivation layer. The insulating layerhas an upper surface, a lower surface opposite to the upper surface, anda first opening connecting the upper surface and the lower surface. Thepatterned conductive layer is configured on the upper surface of theinsulating layer and exposes the first opening. The thermal conductiveblock is configured on the lower surface of the insulating layer.Besides, the thermal conductive block has a top surface, a bottomsurface opposite to the top surface, and a plurality of second openings.The first opening exposes a portion of the top surface of the thermalconductive block to define a device bonding region, and the secondopenings do not communicate with the first opening. The surfacepassivation layer is configured on the patterned conductive layer andthe portion of the top surface of the thermal conductive block exposedby the first opening. The heat-generating element is configured on thesurface passivation layer correspondingly located above the devicebonding region.

According to an embodiment of the invention, a material of the patternedconductive layer is copper foil.

According to an embodiment of the invention, a material of the thermalconductive block includes copper, copper alloy, aluminum, or aluminumalloy.

According to an embodiment of the invention, a material of theinsulating layer includes resin, LCP, or PI.

Based on the above, the package carrier described in the embodiments ofthe invention is formed by two different metal layers with respectivethicknesses. Hence, the relatively thick metal layer can act as athermal conductive block. Besides, the surface of the relatively thickmetal layer can be exposed by openings, and the exposed surface canserve as a device bonding region. When a heat-generating element isconfigured on the package carrier, the heat-generating element isconfigured on the surface of the thermal conductive block, i.e.,configured in the device bonding region. Accordingly, the heat generatedby the heat-generating element can be rapidly conducted to externalsurroundings directly without being blocked by the insulating layer andthe adhesive layer. As such, the package carrier described in theembodiments of the invention can effectively dissipate the heatgenerated by the heat-generating element, and the efficiency and thelife span of the heat-generating element can both be improved.

In order to make the aforementioned and other features and advantages ofthe invention more comprehensible, embodiments accompanying figures aredescribed in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings constituting a part of this specification areincorporated herein to provide a further understanding of the invention.Here, the drawings illustrate embodiments of the invention and, togetherwith the description, serve to explain the principles of the invention.

FIG. 1A through FIG. 1E are schematic cross-sectional views illustratinga manufacturing method of a package carrier according to an embodimentof the invention.

FIG. 2 is a schematic cross-sectional view illustrating that the packagecarrier depicted in FIG. 1E carries a heat-generating element.

DESCRIPTION OF EMBODIMENTS

FIG. 1A through FIG. 1E are schematic cross-sectional views illustratinga manufacturing method of a package carrier according to an embodimentof the invention. With reference to FIG. 1A, in the manufacturing methodof the package carrier of this embodiment, a first metal layer 110, asecond metal layer 120, and an insulating layer 130 configured betweenthe first metal layer 110 and the second metal layer 120 are provided.The second metal layer 120 has a top surface 122 and a bottom surface124 opposite to the top surface 122. The insulating layer 130 has anupper surface 132 and a lower surface 134 opposite to the upper surface132. Specifically, in this embodiment, the thickness T2 of the secondmetal layer 120 is greater than the thickness T1 of the first metallayer 110. Preferably, the thickness T2 of the second metal layer 120 is1˜100 times the thickness T1 of the first metal layer 110. Besides, amaterial of the first metal layer 110 is copper foil, and a material ofthe second metal layer 120 is copper, copper alloy, aluminum, aluminumalloy, or other metal with good conductivity, for instance. A materialof the insulating layer 130 is resin, LCP, or PI, for instance.

With reference to FIG. 1B, a thermal compression process is performed,such that the first metal layer 110, the insulating layer 130, and thesecond metal layer 120 are integrated to form the substrate 101. Namely,by performing the thermal compression process, the first metal layer 110is fixed onto the upper surface 132 of the insulating layer 130, and thesecond metal layer 120 is fixed onto the lower surface 134 of theinsulating layer 130.

With reference to FIG. 1C, a first opening S1 passing through the firstmetal layer 110 and the insulating layer 130 is formed. The firstopening S1 exposes a portion of the top surface 122 of the second metallayer 120 to define a device bonding region 123. In this embodiment, thefirst opening S1 is formed by performing a stamping process, a routingprocess, a laser drilling process, or any other appropriate process, forinstance.

As indicated in FIG. 1D, the first metal layer 110 is patterned to forma patterned conductive layer 110′. The patterned conductive layer 110′exposes a portion of the upper surface 132 of the insulating layer 130.

With reference to FIG. 1D, a plurality of second openings S2 are formedon the bottom surface 124 of the second metal layer 120. The secondmetal layer 120 is divided into a plurality of thermal conductive blocks126 by the second openings S2, and the second openings S2 do notcommunicate with the first opening S1. Namely, the second openings S2 donot communicate with the top surface 122 of the second metal layer.Here, the second metal layer 120 having the second openings S2 can actas thermal conductive blocks 120′, and the second openings S2 can serveas a fluid passage. In addition, according to this embodiment, thesecond openings S2 are formed by performing a photolithography andetching process, a mechanical drilling process, or a laser drillingprocess, for instance.

It should be mentioned that even though the patterned conductive layer110′ is formed before the second openings S2 are formed in thisembodiment, the steps of forming the patterned conductive layer 110′ andthe second openings S2 are not limited herein. According to anotherembodiment, the patterned conductive layer 110′ can also be formed afterthe second openings S2 are formed. In still another embodiment, thepatterned conductive layer 110′ and the second openings S2 can besimultaneously formed if the etching rate is well monitored. In brief,the step of sequentially forming the patterned conductive layer 110′ andthe second openings S2 is exemplary and should not be construed as alimitation to the invention.

As indicated in FIG. 1E, a surface passivation layer 140 is formed onthe patterned conductive layer 110′ and the portion of the top surface122 of the second metal layer 120 exposed by the first opening S1. Inother words, the surface passivation layer 140 is located on thepatterned conductive layer 110′ and in the device bonding region 123.Here, the surface passivation layer 140 serves to protect the patternedconductive layer 110′ and the portion of the top surface 122 of thesecond metal layer 120 exposed by the first opening S1, so as to reducethe oxidation rate. In this embodiment, a material of the surfacepassivation layer 140 is nickel gold, for instance, and the surfacepassivation layer 140 is formed by electroplating, for instance. So far,the fabrication of the package carrier 100 is substantially completed.

The package carrier 100 of this embodiment structurally includes thepatterned conductive layer 110′, the thermal conductive blocks 120′, theinsulating layer 130, and the surface passivation layer 140. Theinsulating layer 130 has the upper surface 132, the lower surface 134,and the first opening S1 connecting the upper surface 132 and the lowersurface 134. The patterned conductive layer 110′ is configured on theupper surface 132 of the insulating layer 130 and exposes the firstopening S1. The thermal conductive blocks 120′ are configured on thelower surface 134 of the insulating layer 130 and have the top surface122, the bottom 124, and a plurality of second openings S2.Specifically, the first opening S1 exposes a portion of the top surface122 of the thermal conductive blocks 120′, so as to define the devicebonding region 123, and the second openings S2 do not communicate withthe first opening S1. The surface passivation layer 140 is configured onthe patterned conductive layer 110′ and the portion of the top surface122 of the thermal conductive blocks 120′ exposed by the first openingS1. That is to say, the surface passivation layer 140 is configured inthe device bonding region 123.

FIG. 2 is a schematic cross-sectional view illustrating that the packagecarrier depicted in FIG. 1E carries a heat-generating element. Withreference to FIG. 2, in this embodiment, the package carrier 100 issuitable for carrying a heat-generating element 20. The heat-generatingelement 20 is configured on the surface passivation layer 140correspondingly located above the device bonding region 123. Here, theheat-generating element 20 is an electronic chip or a photoelectricdevice, for instance, which should not be construed as a limitation tothe invention. For instance, the electronic chip can be an integratedcircuit chip, e.g., a chip module or an individual chip that includes agraphic chip, a memory chip, a semiconductor chip, and so forth. Thephotoelectric device is a light emitting diode (LED), a laser diode, ora gas discharge light source, for instance. In this embodiment, theheat-generating element 20 is an LED, for instance.

Specifically, the heat-generating element 20, e.g., a semiconductorchip, can be electrically connected to the surface passivation layer 140by wire bonding through a plurality of bonding wires 22. Alternatively,the heat-generating element 20, the bonding wires 22, and a portion ofthe package carrier 100 can be encapsulated by a molding compound 24, soas to secure the electrical connection among the heat-generating element20, the bonding wires 22, and the package carrier 100. In addition, theheat-generating element 20 can be directly configured on the surfacepassivation layer 140 correspondingly located above device bondingregion 123. Namely, the heat-generating element 20 is configured on thesurface passivation layer 140 that is made of a metallic material (e.g.,nickel gold) and located above the thermal conductive blocks 120′.Thereby, the heat generated by the heat-generating element 20 can berapidly conducted to external surroundings through the thermalconductive blocks 120′ and the surface passivation layer 140 which ismade of the metallic material. Compared with the related art, in thisembodiment, it is not necessary to additionally attach the thermalconductive blocks to the bottom of the package carrier through theadhesive layer, and the heat generated by the heat-generating element 20need not be conducted through the insulating layer and the adhesivelayer. As a result, the package carrier 100 not only can effectivelydissipate the heat generated by the heat-generating element 20 but alsocan improve the efficiency and life span of the heat-generating element20. Moreover, the manufacturing costs can be reduced.

Note that the way to bond the heat-generating element 20 and the packagecarrier 100 and the type of the heat-generating element 20 are notlimited in the invention. Although the heat-generating element 20described in this embodiment is electrically connected to the surfacepassivation layer 140 of the package carrier 100 by wire bonding, theheat-generating element 20 in another embodiment can also beelectrically connected to the surface passivation layer 140 locatedabove the device bonding region 123 by flip-chip bonding through aplurality of bumps (not shown). In another embodiment of the invention,the heat-generating element 20 can be a chip package (not shown) and isinstalled to the package carrier 100 by conducting a surface mounttechnology (SMT). The way to bond the heat-generating element 20 and thepackage carrier 100 and the type of the heat-generating element 20 areexemplary and should not be construed as limitations to the invention.

In light of the foregoing, the package carrier described in theembodiments of the invention is formed by two different metal layerswith respective thicknesses. Hence, the relatively thick metal layer canact as a thermal conductive block. Besides, the surface of therelatively thick metal layer can be exposed by openings, and the exposedsurface can serve as a device bonding region. When a heat-generatingelement is configured on the package carrier, the heat-generatingelement is configured on the surface of the thermal conductive block,i.e., configured in the device bonding region. Accordingly, the heatgenerated by the heat-generating element can be rapidly conducted toexternal surroundings directly without being blocked by the insulatinglayer and the adhesive layer. As such, the package carrier described inthe embodiments of the invention can effectively dissipate the heatgenerated by the heat-generating element, and the efficiency and thelife span of the heat-generating element can both be improved.

Although the invention has been described with reference to the aboveembodiments, it will be apparent to one of the ordinary skill in the artthat modifications to the described embodiment may be made withoutdeparting from the spirit of the invention. Accordingly, the scope ofthe invention will be defined by the attached claims not by the abovedetailed descriptions.

What is claimed is:
 1. A manufacturing method of a package carrier,comprising: providing a substrate having a first metal layer, a secondmetal layer, and an insulating layer configured between the first metallayer and the second metal layer, wherein a thickness of the secondmetal layer is greater than a thickness of the first metal layer, andthe second metal layer has a top surface and a bottom surface oppositeto the top surface; forming a first opening passing through the firstmetal layer and the insulating layer, the first opening exposing aportion of the top surface of the second metal layer; patterning thefirst metal layer to form a patterned conductive layer; forming aplurality of second openings on the bottom surface of the second metallayer, wherein the second metal layer is divided into a plurality ofthermal conductive blocks by the second openings, and the secondopenings do not communicate with the first opening; and forming asurface passivation layer on the patterned conductive layer and theportion of the top surface of the second metal layer exposed by thefirst opening.
 2. The manufacturing method of the package carrier asclaimed in claim 1, the step of providing the substrate comprising:providing the insulating layer and the first and second metal layersrespectively located at two opposite sides of the insulating layer; andperforming a thermal compression process, such that the first metallayer, the insulating layer, and the second metal layer are integratedto form the substrate.
 3. The manufacturing method of the packagecarrier as claimed in claim 1, wherein the step of forming the firstopening comprises stamping, routing, or laser drilling.
 4. Themanufacturing method of the package carrier as claimed in claim 1,wherein the thickness of the second metal layer is 1˜100 times thethickness of the first metal layer.
 5. The manufacturing method of thepackage carrier as claimed in claim 1, wherein a material of the firstmetal layer is copper foil.
 6. The manufacturing method of the packagecarrier as claimed in claim 1, wherein a material of the second metallayer comprises copper, copper alloy, aluminum, or aluminum alloy. 7.The manufacturing method of the package carrier as claimed in claim 1,wherein a material of the insulating layer comprises resin, liquidcrystal polymer, or polyimide.
 8. The manufacturing method of thepackage carrier as claimed in claim 1, wherein the step of forming thesecond openings comprises photolithography and etching process,mechanical drilling process, or a laser drilling process.
 9. Themanufacturing method of the package carrier as claimed in claim 1,wherein the step of forming the surface passivation layer compriseselectroplating.